Research On Service Unit Based Network Architecture And Its Crucial Techniques

TCP/IP has been prevalent with the rapid development of Internet and achieved great success. It has become the actual industry standard and gotten dominant status in the network world. But with the fast enlargement of network scale and exploitation of diverse applications, now the development of Internet has overstepped the frame of original architecture. The innate shortages of architecture and out-of-order evolution of diversified techniques make the limitations and problems of TCP/IP network emerged continually. People have been cognizant of the importance of network architecture gradually. Now the researches of network architecture in and out of country are in two aspects: The one is to ameliorate TCP/IP. But this is hard to resolve the inborn problems such as QoS, security and expansibility of TCP/IP. The other is to investigate new types of network architecture to resolve the internal problems of TCP/IP according to the characteristic of network techniques and the requirements of network applications.Service Unit based Network Architecture discussed in this dissertation is a new type of non-layered network architecture. This dissertation first analyzes the problems of TCP/IP network architecture in detail and describes the development status of new types of network architecture. Then Service Unit based Network Architecture and its crucial techniques are investigated in deep.The major innovations and contributions of the dissertation are as below:1. The network construct regulation, design solutions and realization model of Service Unit based Network Architecture are proposed. Based on the idea of Service Unit based Network Architecture proposed by Prof. Zeng Jiazhi, this dissertation proposes that in order to construct network of Service Unit based Network Architecture, Service Units are organized by Service Combination according to network requests. Based on this construct regulation, this dissertation proposes the network design solutions and realization model of Service Unit based Network Architecture.2. QoS scheme based on Virtual Circuit between Ports is proposed. Traditional virtual circuit is between nodes and could not make a difference among data flows which are though the same nodes but belong to different ports. So it could not guarantee end-to-end QoS of applications. While in the QoS scheme based on Virtual Circuit between Ports, sockets are directly bound with the marks of Virtual Circuit between Ports. So different services could be provided to the applications that belong to different ports within the same node and end-to-end QoS requirements of application are guaranteed.3. Data transmission rule of Virtual Circuit between Ports is analyzed in this dissertation. Based on this analysis, two reliable data transmission schemes are proposed.(1) Self-adaptive sliding window with accumulative ACK (SASW-AA) protocol for non-instant text data is proposed. Because the path of Virtual Circuit between Ports is fixed, so the sequence of arrived packets is as the same as the sequence of sent packets, that is, the sequence of packets will not be disordered. According to this data transmission rule, in this dissertation, one ACK is used to accumulatively acknowledge a group of packets self-adaptively. SASW-AA protocol could not only resolve the problem of congestion at upper link due to frequent ACKs in traditional sliding window protocol but also guarantee reliable data transmission.(2) Sliding window with immediate retransmission (SWIR) protocol for instant text data is proposed. In the Virtual Circuit between Ports transmission mode, different with datagram mode, as long as disordered packets are received, it is concluded that some packets are lost. To resolve the problem that packets could not be retransmitted in time in traditional sliding window protocol, this dissertation proposes a solution of transmitting lost packets immediately. This solution could avoid unnecessary waiting time and reduce the data transmission delay of instant data.4. Three new survivability algorithms are proposed in this dissertation.(1) Hybrid Shared Path Protection (HSPP) algorithm is proposed. In order to resolve the problem that the success probability of establishing backup paths is low in Path Protection approach, in HSPP algorithm, the Path Protection approach is first used to establish a backup path for the primary path. If the establishment is unsuccessful, then the primary path is dynamically divided into segments. When dividing the primary path, the hop count of its backup segments should be not more than the limitation. HSPP algorithm could not only improve success probability of establishing backup path but also gain a better tradeoff between the recovery time and the resource utilization ratio. (2) A New Route Selection with Shared Risk Link Group (SRLG) Constraint (NRSSC) algorithm is proposed. Different with traditional algorithms, in NRSSC algorithm, SRLG is taken as one part of link cost function and the SRLG links are avoided when selecting the primary paths. Compared with traditional algorithms, the successful protection probability is efficiently improved. Because Differentiated Reliability (DiR) is considered in this algorithm, it could not only provide protection services of different levels but also improve the resource utilization ratio.(3) Fast Reestablished Restoration Algorithm (FRRA) is proposed. In FRRA algorithm, the recovery paths are also established after the failure has occurred. But it is different with previous Restoration algorithms in that it need not wait for the convergence of routing tables. Routing information of other routers in the network is not needed and the task of selecting recovery paths is implemented by Protection Ingress Router according to local source tree, failure information and routing policy. So the recovery time and the data lost ratio are greatly reduced.The reliable data transmission schemes and survivability algorithms of Service Unit based Network Architecture proposed in this dissertation are also suitable for some other networks. In them, the data transmission schemes are also suitable for networks that use fixed paths to transmit data such as ATM and MPLS network. Especially, when used in multicast networks that use multicast tree to transmit data, the reliable multicast protocol could be greatly simplified. The survivability algorithms proposed in this dissertation are also suitable for MPLS and GMPLS networks.